How many parameter would there be in a logistic regression model used to classify reviews into "good" or "bad"?
Nope! Our number of coefficients will be driven by the vocabulary, and we'll use each of those 10K samples to estimate values for those coefficients - so, 'just'  100K samples.  However, word frequency in human languages follows a Zipf distribution => most of those words will be rare, seen in only a few samples (=> won't even be able to determine whether they are useful or not, let alone get good values for coefficients).  For an application like this one, you would probably find most of the value from a few hundred words.